1. Technical Field
The invention relates to an emergency call system including an emergency call device and a method for initiating an emergency call.
2. Related Art
Two data modules, such as subscriber identity module cards (“SIM cards”), are generally employed to use a mobile phone, such as a cellular phone, for initiating conventional as well as emergency calls. When used in a vehicle, the two SIM cards may be employed in the vehicle itself. A regular-use SIM card is used for the conventional calls and an emergency SIM card is used for initiating the emergency calls. When an emergency call is placed, such as when a user presses an emergency button on a mobile phone after an accident, the emergency SIM card transmits an identification key to a network operator. The SIM card provides the network operator with a corresponding identification key that identifies the user. The network operator then verifies that the received identification key corresponds to one of the identification keys recognized by the network operator, and initiates whatever measures are standard for emergency call reception.
When an emergency call is initiated over a network, for example, a cellular network, the cellular phone switches from the regular-use SIM card to the emergency SIM card. This switching may take between 30 and 90 seconds. The cellular phone, which is registered with the network using the regular-use SIM card, unregisters from the cellular network, and subsequently reregisters using the emergency SIM card. This switching may cause precious time to be lost.
Delays in other situations can also occur, such as with operators of rental cars who need to insert their own SIM card in order to be identified by the network operator. Switching between a regular-use and an emergency use SIM card may be necessary when placing an emergency call from a mobile device contained in a rental car so that the network operator may identify the user according to the user's telephone number stored on the emergency SIM card. The network operator may also identify the user according to the cell phone serial number; however, network operators generally do not permit identification via serial number for security reasons.